The Aztec empire dominated Mesoamerica from Mexico and Guatemala to the territories of Salvador and Honduras for nearly 100 years. The people of Aztec civilization migrated from the Pacific Northwest and inhabited the area which became the capital of Mexico, Tenochtitlan. The Aztecs began their reign in 1427 after the leader; Itzcoatl defeated the Tepanecs and gained control of the Mexican basin. The nation's leadership was passed down through inheritance.
The Aztecs made ritual sacrifices. Warriors captured in battles or tributes from vassal states in the form of humans were usually offered up for sacrifice. They needed a steady supply of ritual sacrifice victims. They never used their own people for sacrifice, because it would cause an uprising. The motivation behind the ritual sacrifices is the concept of "tonalli", or animating spirit. The human's tonalli was believed to be located in the blood, which concentrates in the heart when one becomes frightened.
The god's encouraged sacrifice, because they had a hunger for the heart. The Aztecs believe that if they do not sacrifice, all motion stops. This includes the movement of the sun. So when they made sacrifices, the Aztecs believe they were keeping the sun in motion.
There was another reason for these ritual sacrifices, and that reason is cannibalism. They removed the hearts and bodies, and threw them down the temple steps, which supposedly was given to the gods that way. The limbs were removed and cooked. Today it is widely opposed, but at the time cannibalism was a delicacy amongst the Aztecs. Only the Aztec royalty were allowed to take on cannibalism. The hands and thighs were the Aztec's favorite parts of the body to eat.
The Aztecs had a single ruler, called the emperor, and a social class system that consisted of three social classes.